The present invention relates, in general, to high density data storage and retrieval systems and more particularly to systems capable of storing immense quantities of digital data in a short period of time and in a small space and for effectively retrieving such data.
A great deal of research has gone into the development of systems for the effective and efficient storage of large quantities of data, and to systems for retrieving that data rapidly and effectively. Humans relate to images, and it is particularly in the storage and retrieval of digital representations of various images that major problems occur. For example, the storage of digital data representing a single television image may require 0.5 million bits of data, or more. Recording a typical television program, wherein the television transmission provides 30 frames or images per second requires storage of digital representations of 100,000 frames per hour, so the storage of one hour's worth of television transmission would require storage of 50 billion bits of data. Conventional optical disc storage systems can only store a few frames, so the digital storage of television or related information has been impractical.
Another problem in the storage of digital representations of images and other high density digital data is the difficulty of retrieving such data, for the sheer volume of the data makes recovery extremely difficult. Parallel storage and recovery increases speed, but places stringent requirements on the recording medium, as well as on the equipment for producing the data to be stored or retrieved. Thus, there is a real and growing need for an extremely high volume digital data storage and retrieval system which not only records large quantities of data on a two-dimensional storage medium, but which provides high resolution image recording and storage. In addition, there is a need for a system for rapidly and nondestructively recovering such stored data and for a system which permits selective erasure of stored data.